She was a friend of first lady Jacqueline Kennedy and a political benefactor who funnelled hundreds of thousands of dollars to former presidential candidate John Edwards that was used to hide his mistress.

Her death yesterday was confirmed by Alexander Forger, her personal lawyer for the past 40 years, and her grandson Thomas Lloyd.

A jury later acquitted him on a campaign finance charge and was deadlocked on five other counts. Mrs Mellon was not accused of breaking any laws.

Friends said Mrs Mellon should be remembered more for her contributions to the world of horticulture, art and fashion than the scandal that marked her last years.

"She's a remarkable person," said her friend, interior designer Bryan Huffman of North Carolina. "The last standing true American aristocrat."

Her family said she died of natural causes at her beloved 4,000-acre Oak Spring Farms in Virginia's horse country, where she entertained royalty, stars and politicians but from which she rarely ventured.

Rachel Lowe Lambert Lloyd Mellon's mother gave her the pet name "Bunny," which stuck with her throughout her life, Mr Huffman said.

Her grandfather, Jordan W Lambert, created Listerine. Her father, Gerald Lambert, built a company that made everything from Dentyne to Schick razors before it was sold to Pfizer for 110 billion dollars (66 billion) in 2000.

In 1932, she married Stacy Barcroft Lloyd Jr, a businessman and horse breeder. After their divorce, she married his friend Paul Mellon - at the time, reportedly, the world's richest man. Mr Mellon, a renowned art collector, philanthropist and thoroughbred breeder, died in 1999 aged 91.

Mr Huffman, who introduced Mrs Mellon to Mr Edwards, said the former presidential candidate reminded her of John Kennedy.

"She liked what he said about the 'Two Americas,'" Mr Huffman said. "She believed deeply in what he was saying."

Andrew Young, an aide to Mr Edwards, wrote in his tell-all book The Politician that Mrs Mellon became so distraught when the media attacked Mr Edwards over a 400 dollar (£240) haircut that she sent him a letter offering to help.

Mrs Mellon eventually gave Mr Edwards more than 6 million dollars (£3.6 million), Mr Young said.

He described how the campaign used the so-called Bunny Money to hide Ms Hunter.

Mrs Mellon sent cheques to Mr Huffman inside boxes of chocolate, and Mr Huffman would direct them to the campaign, Mr Young wrote. Mrs Mellon's lawyer said she had no idea the money was going to hide a mistress.

Her grandson, Lloyd, said: "I think she was trying to help (Edwards) for the right reasons, believed in him, and I think frankly he just took advantage of a lot of opportunities that she gave him."

Mr Huffman said his friend remained in good spirits despite the Edwards distraction. She had endured worse, including the 2008 death of her daughter Eliza, who had been left quadriplegic when hit by a car years earlier.

She had a son, Stacy Barcroft Lloyd III, and two step-children, Timothy Mellon and Catherine Warner. The daughter was married to former US Senator John Warner.

Mrs Mellon was a "legend in design and gardening circles" who had a low-key style that was eloquent but unpretentious, Mr Huffman said.

A self-taught botanist, Mrs Mellon was asked by her friend Jacqueline Kennedy to design the White House Rose Garden.